Are there other ways to get an object property in JavaScript?

Question

I have a dataLayer array that has objects inside it:

dataLayer[3]
Object {event: "gerar-evento", event-category: "Chat", event-acion: "Vendas", event-label: "Pré Fixo 15"}

When I try to select a property of this object I get an error

If I try:

dataLayer[3].event

It works fine, returning gerar-evento, but if I try:

dataLayer[3].event-label

I get this error: ReferenceError: label is not defined

Is there another way to select a property from an object? What am I doing wrong?

score 5 · Accepted Answer · answered Aug 30 '14 at 03:33

5

You need to use bracket notation since event-label is not a valid identifier

dataLayer[3]['event-label']

answered Aug 30 '14 at 03:33

Arun P Johny

2

In case it's not clear why `event-label` isn't a valid identifier: it's an expression that subtracts a variable called `label` from one called `event`. – Wyzard Aug 30 '14 at 03:36

Mimo · Answer 2 · 2014-08-30T03:47:00.277

In JavaScript you have two ways to get object properties:

Dot notation: object.property
Bracket notation: object['property-with-dash'] which is the one you have to use in your case:

dataLayer[3]['event-category']

Also with the bracket notation, you can use variables to get properties out of the object, for example:

 var eventName = 'event-category';
 dataLayer[3][eventName]

would give you the same result.

2 Answers2